title: Preparation and characterization of D, L-PLA loaded 17-β-Estradiol valerate by emulsion/evaporation methods.
abstract: PLA microparticles containing 17-β-estradiol valerate were prepared by an emulsion/evaporation method in order to sustain drug release. This system was characterized concerning particle size, particle morphology and the influence of formulation and processing parameters on drug encapsulation and in vitro drug release. The biodegradation of the microparticles was observed by tissue histological analysis. Scanning electron microscopy and particle size analysis showed that the microparticles were spherical, presenting non-aggregated homogeneous surface and had diameters in the range of 718-880 nm (inert micro-particles) and 3-4 µm (drug loaded microparticles). The encapsulation efficiency was ∼80%. Hormone released from microparticles was sustained. An in vivo degradation experiment confirmed that microparticles are biodegradable. The preparation method was shown to be suitable, since the morphological characteristics and efficiency yield were satisfactory. Thus, the method of developed microparticles seems to be a promising system for sustained release of 17-β-estradiol.
authors.affiliation: Department of Pharmaceutical Sciences, Laboratory of Pharmaceutical Technology, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Silvia R P
authors.initials: SR
authors.lastname: Machado
authors.forename: Laureluci O
authors.initials: LO
authors.lastname: Lunardi
authors.forename: Alan P
authors.initials: AP
authors.lastname: Tristão
authors.forename: Juliana M
authors.initials: JM
authors.lastname: Marchetti
mesh_terms: D000818:Animals; D003692:Delayed-Action Preparations / Q000737:chemistry* / Q000378:metabolism; D004339:Drug Compounding / Q000379:methods*; D004655:Emulsions; D004958:Estradiol / Q000008:administration & dosage* / Q000031:analogs & derivatives*; D019344:Lactic Acid / Q000737:chemistry* / Q000378:metabolism; D008297:Male; D008863:Microspheres; D010316:Particle Size; D011091:Polyesters; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D003692:Delayed-Action Preparations; D004655:Emulsions; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide); D004958:Estradiol